Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g-1 and 5.18 mmol·g-1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with-SO3 H in resin. The removal process was studied as a function of temperature, H3 PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g-1 resin when the operating parameters were T = 50 ℃, H3 PO4 content = 27.61 wt%and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol-1. The overall reaction process was mainly controlled by pore diffusion.

Adsorption equilibrium, kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid–nitric acid aqueous solution by strong acid cation resin

The separation of Ca2+and Mg2+ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer.This paper studied the adsorption equilibrium,kinetics,and dynamic separation of Ca2+and Mg2+ions by strong acid cation resin,and the effects of phosphoric acid and nitric acid on the adsorption process were investigated.The results reveal that the adsorption process of Ca2+and Mg2+ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g-1 and 1.83 mmol·g-1,respectively.The adsorption kinetics of Ca2+and Mg2+ions on resin fits better with the pseudo-first-order model,and the adsorption equilibrium in pure water is reached within 10 min contact time,while at the present of phosphoric acid,the adsorption rate of Ca2+and Mg2+ions on resin will go down.The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution,but the dynamic operation should control the flow rate of mix acid solution.Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.

USE OF CATION EXCHANGE RESIN IN SYNTHESIS OF N-SUBSTITUTED-1-AMINOALKANEPHOSPHONATE AND-PHOSPHINIC ACIDS

Strongly acidic cation exchange resin(1x1,H form)has been successfully used as a catalyst in synthesis of diphenyl N-benzyloxycarbonyl-1-aminobenzylphosphonate, N-benzyloxycarbonyl-1-aminobenzylphenylphosphinic acid and N-p-tolylsulfonyl-1-aminobenzyl phenylphosphinic acid in high yields.

Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Removal of Co(Ⅱ) from aqueous solutions by NKC-9 strong acid resin

A strong acidic ion exchange resin(NKC-9)was used as a new adsorbent material for the removal of Co(Ⅱ)from aqueous solutions.The adsorption isotherm follows the Langmuir model.The maximum adsorption capacity of the resin for Co(Ⅱ)is evaluated to be 361.0 mg/g by the Langmuir model.It is found that 0.5 mol/L HCl solution provides effectiveness of the desorption of Co(Ⅱ)from the resin.The adsorption rate constants determined at 288,298 and 308 K are 7.12×10-5,8.51×10-5and 9.85×10-5s-1, respectively.The apparent activation energy(Ea)is 12.0 kJ/mol and the adsorption parameters of thermodynamic are-H Θ=16.1 kJ/mol,-SΘ=163.4 J/(mol·K),-G Θ 298 K=-32.6 kJ/mol,respectively.The adsorption of Co(Ⅱ)on the resin is found to be endothermic in nature.Column experiments show that it is possible to remove Co(Ⅱ)ions from aqueous medium dynamically by NKC-9 resin.

树脂载钯双功能催化剂的制备及其催化碳四烯烃临氢叠合反应

基于碳四烯烃叠合反应工艺,设计并制备了酸性树脂(KC110、Amberlyst35)载钯双功能催化剂,用于一步法催化1,3-丁二烯选择性加氢和异丁烯叠合反应。借助电子微区探针分析(EPMA)、N 2物理吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等手段对其物化性质进行表征,并进一步考察了双功能催化剂在碳四烯烃临氢叠合反应过程中的催化性能。结果表明:0.10%Pd/KC110双功能催化剂负载的钯纳米颗粒主要分布在树脂大孔表层结构,平均粒径为3~10 nm,且树脂载体本身的酸性和孔结构保存完好;在反应温度为25℃、压力为1.4~1.6 MPa、质量空速为2.7 h-1、氢气/丁二烯摩尔比为1.5的条件下进行0.10%Pd/KC110催化碳四烯烃临氢叠合反应,1,3-丁二烯可以完全脱除,异丁烯转化率高于81.5%,叠合产物中碳八选择性为75.1%。

强酸性阳离子交换树脂对铅的吸附行为及机理

通过静态吸附实验,研究了Pb2+在001×7强酸性阳离子交换树脂上的吸附行为,并从热力学和动力学方面对吸附过程进行了分析,用红外光谱的方法探讨了001×7树脂吸附Pb2+的机理。结果表明:在所研究的浓度范围内,Pb2+在001×7树脂上的吸附平衡数据符合Freundlich等温吸附方程,吸附为自发进行的放热过程;液膜扩散为Pb2+在001×7树脂上吸附速率的主要控制步骤,随着振荡频率的增加,吸附速率会逐渐增大;最佳的吸附pH在4左右,用3mol/L的硝酸对饱和树脂进行洗脱再生,洗脱率可达98%以上;298K温度下树脂的静态饱和吸附容量为414mg/g(湿树脂)。

阳离子交换树脂催化合成丙烯酸丁酯

从 6种常见的强酸性苯乙烯系阳离子交换树脂中选择了催化活性最高的D0 0 1cc树脂作为酯化合成丙烯酸丁酯的催化剂 ,得到了适宜的反应条件为 :醇酸摩尔比 1.2∶1,每摩尔丙烯酸的催化剂用量 2 0 g树脂 ,每摩尔丙烯酸的带水剂 (环己烷 )用量 6 6 .7mL ,反应温度 10 1～ 10 5℃ ,反应时间 3h ,丙烯酸的酯化率 >97%。该树脂催化剂具有优良的重复使用性。利用气相色谱 质谱联用仪分析产物 ,结果表明 ,该阳离子交换树脂具有与浓硫酸相当的催化效果。

强酸性阳离子交换树脂催化合成丁二酸二丁酯

用强酸性阳离子交换树脂催化丁二酸和正丁醇的酯化反应 ,合成了丁二酸二丁酯。研究了影响反应的因素和催化剂的重复使用性能 ,在丁二酸 2 5mmol,正丁醇 2 0 0mmol和催化剂 1 .5g,回流分水 1 2 0min的反应条件下 ,酯化率达 95 .7%。催化剂套用 5次 ,其活性未发生明显变化。

改进型无溶剂法工艺合成环氧大豆油的研究

以732#强酸性阳离子交换树脂为催化剂,采用改进型无溶剂法工艺合成环氧大豆油。优化工艺条件为:大豆油∶H2O2∶甲酸为1∶(0.60～0.65)∶(0.13～0.15)(W/W/W),催化剂用量3%～4%(以大豆油计),相转移稳定剂用量0.2%～0.3%(以大豆油计),反应温度65～70℃。所得产品色泽浅(<150),环氧值高(≥6.5%),热稳定性好(保留率>96%),产品质量达到或优于国优标准,催化剂可重复使用8次,再生容易,无腐蚀,环境污染小。

丁二酸催化酯化-吸附脱水联合工艺

以阳离子交换树脂NKC-9固体酸为催化剂、丁二酸和甲醇为原料,采用分子筛吸附脱水技术合成丁二酸二甲酯.考察了原料配比、催化剂用量和反应时间等因素对酯化反应的影响,通过实验得到了最佳酯化反应工艺条件:n甲醇/n丁二酸=3.0:1,NKC-9为3.5%(ω)、反应温度≤120℃、反应时间4h,在该条件下丁二酸的转化率达到98.86%.催化剂重复使用6次后,丁二酸的转化率仍可达到98.09%.利用红外光谱、色谱-质谱对产品进行分析,结果显示,产物中没有副产物,反应选择性很高.

用离子交换树脂催化水解醋酸甲酯的反应动力学研究

研究了在常压下、温度为３０８～３２８Ｋ的范围内，用阳离子交换树脂作催化剂的醋酸甲酯催化水解宏观反应动力学。建立了实验条件下的动力学模型。研究了反应温度、催化剂浓度、水酯比、催化剂装填方式及进料中含甲醇等因素对催化水解的影响。实验数据采用拟均相二级反应动力学模型进行回归，得出醋酸甲酯催化水解的正逆反应活化能为３５．５和２９．５ｋＪ／ｍｏｌ。与催化剂浓度关联的最终速率表达式为：ｋ＋＝（５．３９２７９×１０－１０Ｃ－２．０７２０５９×１０－８）ｅｘｐ（－４．２７０／Ｔ）ｋ－＝（５．９１０６６×１０－１０Ｃ－１．５１５４３×１０－８）ｅｘｐ（－３．４２８／Ｔ）

改性阳离子交换树脂催化合成双酚F

筛选了可用于催化苯酚、甲醛缩合合成双酚F的阳离子交换树脂催化剂,研究了以负载AlCl3的大孔型低交联度阳离子交换树脂为催化剂催化合成双酚F的工艺条件。结果表明,苯酚与甲醛的物质的量比为5/1,75℃反应2.5h,双酚F的收率可达80%以上,催化剂可以重复使用。

丙烯酸高级醇酯合成工艺的研究

以大孔强酸性阳离子交换树脂为催化剂 ,对羟基苯甲醚作阻聚剂 ,合成了丙烯酸 C8～ C16 正构偶数碳醇酯。实验结果表明 ,D0 0 1cc树脂具有良好的催化活性和稳定性 ,丙烯酸酯收率达 94

耐温强酸性阳离子交换树脂催化合成乙酸丁酯

开发了耐温强酸性阳离子交换树脂催化剂，采用此催化剂，以乙酸和正丁醇为原料合成了乙酸丁酯。用13C核磁共振光谱表征了耐温强酸性阳离子交换树脂催化剂的结构；在工业生产条件下，对比了不同强酸性阳离子交换树脂催化剂的活性；以耐温强酸性阳离子交换树脂为催化剂，考察了进料量对乙酸转化率的影响及催化剂的稳定性。实验结果表明，以耐温强酸性阳离子交换树脂为催化剂合成乙酸丁酯，在反应釜温度120℃、分馏柱顶部温度91～92℃、正丁醇与乙酸摩尔比1．02、进料量60mL／h的条件下，乙酸的转化率为95．1％，达到了采用硫酸催化剂时的水平。耐温强酸性阳离子交换树脂催化剂的寿命在500h以上，稳定性好，具有较好的工业化前景。

固体酸催化合成乙酸异丁酯的研究

研究了几种固体酸催化剂用于异丁醇与乙酸酯化合成乙酸异丁酯的催化性能。结果表明 ,对甲苯磺酸、磷钨酸、磷钼酸都具有与硫酸相近的催化效果 ,但在连续使用时其催化活性逐渐降低 ;添加少量磷酸或抗坏血酸到磷钨酸催化剂中 ,可大大提高其连续使用的稳定性 ;强酸性阳离子交换树脂和 SO2 - 4 / Ti O2 固体超强酸都具有高的催化活性和优良的重复使用稳定性 ,其中前者呈颗粒状 ,易于分离 。

强酸性离子交换树脂催化合成乙酸正丁酯动力学

为了获得D072型强酸性离子交换树脂催化剂合成乙酸正丁酯反应动力学方程，在间歇釜式反应器中，消除内外扩散后，测定不同反应条件下乙酸浓度随时间的变化，反应体系按拟均相处理，用初始速率法回归估算动力学模型参数。在催化剂平均粒度小于0．074mm，搅拌速度大于150r．min^-1时，可基本消除内外扩散的影响。在常压，催化荆用量为0．01665-0．08333gcut.gA-1，温度为326．2-358．2K的条件范围，获得的动力学模型参数为：k0=8．86×10^4L·mool-1min-j·gul-1，E,=60728．86J．mol-1，平衡常数受温度的影响不大。在实验条件范围对获得的动力学方程进行了验证，最大相对偏差小于8．3％，计算值与实验值符合较好。

用强酸性阳离子交换树脂分离不锈钢酸洗废水中的铁

通过静态吸附试验,研究了001×7强酸性阳离子交换树脂吸附Fe3+的行为,从动力学角度分析了吸附过程。结果表明:在298 K下,001×7树脂对废水中Fe3+的静态饱和吸附容量为65.3 mg/g(干树脂);吸附平衡符合Freundlich等温吸附式;根据动边界模型,颗粒扩散为001×7树脂吸附Fe3+的主要控制步骤,吸附速率与树脂性质、温度有关,与搅拌强度无关;用质量浓度7.4 g/L的硫酸溶液洗脱负载树脂,铁洗脱率达99.5%,树脂再生后可重复使用。

大孔强酸性阳离子交换树脂催化合成柠檬酸三丁酯

以大孔强酸性阳离子交换树脂为催化剂,研究了环保型增塑剂柠檬酸三丁酯的合成及分离提纯工艺条件。通过对诸多反应影响因素的考察,得到了最佳反应条件:n(柠檬酸):n(正丁醇)=1:4.5,催化剂用量为20%(以柠檬酸计算),反应温度130℃,酯化率94.3%。研究了反应产物的精制条件,最终得到纯度大于99.5%的产品。